Yes, whether an entity is drawn is based on the distance from the player. Various entity types can override that distance, which is why some show up farther away than others. There's actually two distances, a "start fading out" distance, and a "no longer seen" distance.
I don't see a simple slash command or anything to override that -- it appears to be a hardcoded behavior. Modding the client to override it looks doable, if you're comfortable making a few changes to the exe.